sifImport: Use size_t as appropriate.
sifImport: Use size_t as appropriate.

For 'int' multiplications the assertion in sifImport:239
fails for files > 2GB.

dstoe/vigra,funkey/vigra,timoMa/vigra,martinsch/vigra,dstoe/vigra,cha007/vigra,mmuellner/vigra,psteinb/vigra,xiwei-zhang/vigra,mmuellner/vigra,DaveRichmond-/vigra,dagophil/vigra,psteinb/vigra,capturePointer/vigra,martinsch/vigra,cha007/vigra,funkey/vigra,martinsch/vigra,hmeine/vigra,ThomasWalter/vigra,DaveRichmond-/vigra,dstoe/vigra,dagophil/vigra,psteinb/vigra,stuarteberg/vigra,dagophil/vigra,hmeine/vigra,hmeine/vigra,stuarteberg/vigra,cbecker/vigra,kod3r/vigra,cbecker/vigra,ThomasWalter/vigra,stuarteberg/vigra,xiwei-zhang/vigra,kod3r/vigra,ThomasWalter/vigra,timoMa/vigra,hmeine/vigra,hmeine/vigra,kod3r/vigra,ThomasWalter/vigra,funkey/vigra,dstoe/vigra,stuarteberg/vigra,mmuellner/vigra,DaveRichmond-/vigra,cha007/vigra,stuarteberg/vigra,funkey/vigra,xiwei-zhang/vigra,martinsch/vigra,ThomasWalter/vigra,xiwei-zhang/vigra,timoMa/vigra,cha007/vigra,cbecker/vigra,kod3r/vigra,dagophil/vigra,dstoe/vigra,funkey/vigra,ThomasWalter/vigra,timoMa/vigra,psteinb/vigra,dagophil/vigra,xiwei-zhang/vigra,stuarteberg/vigra,stuarteberg/vigra,kod3r/vigra,timoMa/vigra,DaveRichmond-/vigra,xiwei-zhang/vigra,funkey/vigra,timoMa/vigra,cbecker/vigra,DaveRichmond-/vigra,mmuellner/vigra,cbecker/vigra,psteinb/vigra,martinsch/vigra,capturePointer/vigra,capturePointer/vigra,capturePointer/vigra,ThomasWalter/vigra,cbecker/vigra,dstoe/vigra,cha007/vigra,hmeine/vigra,xiwei-zhang/vigra,mmuellner/vigra,hmeine/vigra,cha007/vigra,psteinb/vigra,martinsch/vigra,mmuellner/vigra,funkey/vigra,kod3r/vigra,capturePointer/vigra,dagophil/vigra,capturePointer/vigra,mmuellner/vigra,dagophil/vigra,dstoe/vigra,DaveRichmond-/vigra,psteinb/vigra,cha007/vigra,kod3r/vigra,timoMa/vigra,capturePointer/vigra,DaveRichmond-/vigra